Wrong 12bit to 8 bit mapping with imaqDisplayImage() after update from imaq1394 to IMAQdx.

[Neutronensturm]

Hi,

on two machines we have the same c++ program running. We are acquiring images with imaq1394 from a Hamamatsu Orca AG (12 bits), display a live image and then save the same image to disk as 16 bit TIFF. Our system with the old imaq1394 behaves like we want: the imaqDisplayImage() displays our 12 bit image correctly. It scales the IMAQ_IMAGE_I16 image down 8 bits (we set the mapping to IMAQ_FULL_DYNAMIC).
On the machine having IMAQdx installed I only see the lower 8 bits displayed, the live image looks overilluminated. Still the saved 16 bit TIFF images are correct. Both machines have Vision 8.2 installed. So the only difference is the installed IMAQdx.

Hope for a helping suggestion,

Fabian

[Elmar_NI]

Hello Fabian,

yes its a different between the old legacy 1394 and the new imaqdx driver. But you are able to use also the old driver in the new software version. For more information about the functions of the new driver please read the function ref. manual. You can find the info under Start/Programme/National Instruments/Vision/Documentation/Imaqdx.

Kind regards,

Elmar

[JohannS]

In NI-IMAQdx we attempt to query the camera for its actual bit depth. I do not know about the Orca AG, but some cameras incorrectly report their actual bit depth. Be sure to check your 16-bit Pixel Representation settings in MAX. You can override the "Use hardware default" and set the exact settings of your camera. For the Hamamatsu I believe you want to use 12-bit, LSB, and big-endian. See attached screenshot for 16-bit settings.



Hope this helps.

JohannS

Message Edited by JohannS on 09-04-2007 09:27 AM

[DeltaJ]

Hi,

I am currently experiencing a very similar problem with an Orca camera and IMAQdx. When operating properly the camera loads up settings and our baseline (for a dark pixel) is about 200AU. However sometimes for no obvious reason the camera will reset to some values - typically around 2000AU for a dark pixel. Unlike the poster above when we acquire a .tiff image the intensity remains at 2000AU. On screen during life feed the images appear over-exposed. In MAX a lot of changing of settings and values can often force the cameras back into their proper settings - however we haven't idenitfied a proper sequence for this - it appears just random settings changes will eventually force the system to move to the correct baseline.

This issue is also happening across multiple cameras we are working with. All are Hamamatsu ORCA-03G.

Unfortunately we cannot yet figure out how to get the cameras to change from the high baseline readings to the low baseline readings programmatically.

If anyone has any suggestions they would be greatly appreciated.

Many thanks,

David